* Fuse: Check the power window fuse in the fuse box (usually under the hood or inside the vehicle). A blown fuse is a common cause.
* Window Regulator: This mechanism is responsible for moving the window. It could be broken, jammed, or worn out. This is a common failure point in older vehicles.
* Window Motor: The motor itself might be faulty.
* Wiring: Wires can become frayed, disconnected, or corroded, preventing power from reaching the motor.
* Switch: The power window switch on the driver's or passenger's door could be malfunctioning.
* Master Switch (Driver's Side): The master switch controls all windows, and a problem here could affect the passenger side.
To diagnose the problem, you'll need to systematically check these components. A repair manual specific to a 1999 Ford Windstar would be very helpful. You can often find these online. If you're not comfortable working on the vehicle yourself, a qualified mechanic can quickly diagnose and fix the problem.
